Google is also serving a different market (average of lower-end phones on lower-end networks); however, I worry that every day Google's stance on apps and app review starts to look more and more like Apple's.
WRT to Apple enabling this: I imagine developers could get into a bit of a versioning hell-scape there if they were decouple updates of different modules in their app (do you know if your app is working with FeatureA v1, v2, v3, or not at all? How about FeatureB?) If Apple were to do this it would look something like app extensions do today (separate binary stored within the IPA - that's possibly thinned out and rehydrated on device); probably with very little control over what's loaded (similar to how they did rollouts: this percent on this date and nothing else)
